Transportation particulates, particularly diesel, used to kill about as
many Americans yearly as did coal, but
diesel fuel is being cleaned up.
There is significant cost to agriculture and
ecosystems as well.

EPA estimates that
the recent shift to ultra low sulfur diesel (pollution control devices
are destroyed by sulfur) will prevent 8,300 premature deaths, 5,500
case of chronic bronchitis, and 18,000 cases of acute bronchitis in
children. EPA does not provide estimates on how many deaths and
illnesses are still caused by transportation pollution. (Note: it would
be useful to Americans if EPA were called upon to provide estimates of
the health and environmental harm done by various energy sources. It
would facilitate better policy decisions.)

The rest of this answer repeats
information, more or less, in the answer to coal #2.
There is a connection
between particulates and asthma.

Daily asthma presentations to
the Emergency Department of Royal Darwin Hospital
and 24-hour mean PM10 concentrations, Darwin, April – October
2000PM10
are particles less than 10 millionths of a meter.

Check out your part of the US on a map of premature mortality due to PM2.5
(particles less than 2.5 millionths of a meter) on an introduction to
the health effects
of various pollutants. Ozone
is responsible for 10 - 20% of summertime respiratory emergency visits
in the US northeast and harms other animal and plants as well,
particularly long-living plants such as trees.

Bell, et al,
looks at 95 large American cities and estimates 4,000 Americans die
yearly from short term effects of higher ozone concentrations. The
National Academy of Sciences calculates 30,000 lives
could be saved annually worldwide by 2030 simply by producing less
ozone by reducing natural gas emissions 20%.

Nitrogen oxides (NOx) contribute to the formation of ozone. NOx also
cause
cardiovascular disease and respiratory disease, but can harm other
parts
of the body as well. Along with sulfur dioxide, it is a major cause
of acid rain (15% to 25%). NOx harm the soil, with great cost to both
agriculture
and forests. The majority of US ground level ozone in most urban areas,
almost
half nationwide, comes from transportation.

World Health Organization estimates that 3 million
die annually from outdoor air pollution (plus 1.6
million from indoor air pollution from the use of solid fuels such
as dung, wood, crop waste, or coal.)